Vic
Take a close look at the seam under the bumper once you remove it, you wont miss it. It only takes a pin prick hole for water to find its way in. i spent a lot of time pouring water over certain areas to treble check, being methodical and working from bottom to top. As you can see by the pics i used tape to go over the holes etc to eliminate them, also rather than a hose, fill a watering can or bottle and pour this seemed more effective in locating the leak. Good luck and hope you find something, please let us know